Skip to Main content Skip to Navigation
Journal articles

Colloidal dispersions of tannins in water-ethanol solutions

Abstract : The molecular interactions of grape-seed tannins dissolved in water-ethanol solutions have been studied through small angle neutron scattering, light scattering, and physical separation techniques. Through selective precipitation in different solvent mixtures, three populations of tannin macromolecules have been identified: T1 (2% of the total tannin), which forms colloidal particles when the ethanol content of the solvent is brought below phi(A) = 0.6; T2a (33% of the tannin), which phase-separates below phi(A) = 0.08 in ionic conditions that are typical of wine; and T2b (65% of the tannin), which remains in solution regardless of ethanol content. Each population remains molecularly dissolved (i.e., it does not form any association structures such as stacks or micelles) until the threshold where dense colloidal particles are formed through nucleation and growth. The colloidal dispersions are metastable, due to the adsorption of organic acids on the particle surfaces; increasing ionic strength and reducing ethanol content cause the loss of this metastability and the aggregation of the particles
Document type :
Journal articles
Complete list of metadata

https://hal.inrae.fr/hal-02658575
Contributor : Migration Prodinra <>
Submitted on : Saturday, May 30, 2020 - 12:29:10 PM
Last modification on : Saturday, June 19, 2021 - 4:13:32 AM

Links full text

Identifiers

Citation

Drazen Zanchi, Aude Vernhet, Celine Poncet-Legrand, Damien Cartalade, Christophe Tribet, et al.. Colloidal dispersions of tannins in water-ethanol solutions. Langmuir, American Chemical Society, 2007, 23 (20), pp.9949-9959. ⟨10.1021/la700694b⟩. ⟨hal-02658575⟩

Share

Metrics

Record views

78